This invention relates to a reactor and a method for making a reactor containing a structure.
Reactors containing structures with catalyst have been described, for example tubular reactors used in reforming. Structures, compared to random packings such as catalyst pellets, can produce a lower pressure drop, are not easily fluidized, and are not prone to settling or crushing. Since tubular reactors are often externally heated or cooled, another important characteristic of the reactor is related to heat transfer between the external heat source/sink and the process fluid within the reactor. Depending on the geometry of the packing, heat transfer in reactors with random packings may be greater than reactors with structures since the process fluid within the reactor with random packing is flowing randomly between the center of the tube and the tube wall.
Davidson, U.S. Pat. No. 4,340,501, describes a structure in a reactor vessel where the fluid is intermittently but controllably brought into contact with the vessel walls. As a result, Davidson states that it is possible to obtain the smooth-flow characteristics of honeycomb structures with the heat transfer characteristics of particulate beds.
In the invention according to Davidson, the process for contacting a fluid with the walls of a vessel is characterized by causing the fluid to flow alternatingly (a) through a structure within the vessel, and (b) through a space between the structure and the vessel walls. Davidson also describes an apparatus for carrying out the process comprising a vessel and a structure inside the vessel.
Since heat transfer is admittedly important, it would be desirable to further increase heat transfer between a heat source/sink outside the reactor vessel and the fluid inside the vessel.
The present invention may be particularly useful for a process and reactor for steam reforming hydrocarbons in which the process gases comprise steam and a gaseous or vaporized hydrocarbon and the structure comprises a steam-hydrocarbon reforming catalyst.